Resolve "unwanted interaction between different ExpCalcCounters"

Closes #2149

See merge request !2961

Overloading __new__ allows to modify the created object class,
a new class deriving from the class is made at each call, hence
producing different classes - then there is no need for a metaclass

Musst sampling counter

See merge request !2915

As the image widget is per detector, skip the reset of the view

Closes #2148

See merge request !2960

As the image widget is per detector, skip the reset of the view

Closes #2148

See merge request !2959

Resolve "[test] channel test test_with_another_process fails"

Closes #2146

See merge request !2957

Resolve "log server cannot store logs anymore"

Closes #2145

See merge request !2955

Resolve "tmux is blocking access to bliss session"

Closes #2134

See merge request !2947

Improve live plot image

Closes #2142 and #2102

See merge request !2946

Resolve "hotfix for too many connections done in parallel at channel init"

Closes #2086

See merge request !2895

Resolve "nexus_writer: Redis is loading the dataset in memory"

Closes #1454

See merge request !2945

Fix Flint help URL

See merge request bliss/bliss!2949